Vector analysis of cross cylinder LASIK with the NIDEK EC-5000 excimer laser for high astigmatism.

PURPOSE: To evaluate visual outcomes of LASIK in eyes with high astigmatic refractive errors with low spherical component.

METHODS

We prospectively evaluated cross cylinder LASIK in patients with high astigmatic eyes with low spherical component over a 2-year period. All laser surgeries were performed with the NIDEK EC-5000 excimer laser. We used power vectors (M [spherical equivalent] and J(0), and J(45) [cylinder]) to analyze the astigmatic results. Main outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and complications.

RESULTS

Thirty-four eyes of 22 patients were included. Patients were followed for 21.8+/-3.7 months. At the last examination, UCVA of 20/40 or better was observed in 33 (97.1%) eyes. Best spectacle-corrected visual acuity after LASIK improved significantly in comparison to BSCVA before surgery (P<.005). Mean preoperative cylinder was -4.73+/-0.89 diopters (D) (range: -4.00 to -7.00 D), which decreased to -0.29+/-0.47 D (range: 0.00 to -1.50 D) at last follow-up (P<.001). Reduction in the magnitude of power vectors was 92.4% for M, 103.2% for J(0), and 76.4% for J(45). No cases of post-operative astigmatic regression or corneal haze were observed.

CONCLUSIONS

Cross cylinder LASIK with the NIDEK EC-5000 excimer laser is a successful procedure for correcting high astigmatism and improving vision.